Techniques, Tricks, and Stratagems of Oral Cavity Computed Tomography and Magnetic Resonance Imaging

Round 1

Reviewer 1 Report

I consider this review about the currently available imaging techniques for oral diseases, it is very well structured and it has been able to document everything very exhaustively. In addition, it seems to me a topic of considerable interest, since diagnosis is fundamental in the field of dentistry, and it is very interesting that dentists know all these diagnostic tools.

 

As for the meteorology, it is correct, and in particular, the images in the article have seemed very helpful, visual and explanatory. The results and the discussions are very well explained and argued.

Congratulations to the authors!

Author Response

We thank the reviewer 1 for the favorable opinion regarding our manuscript.      

Reviewer 2 Report

This is an interesting article about oral cavity imaging techniques. The authors analyzed the currently available imaging techniques for oral diseases, with particular attention to the role of DWI, DCE-PWI, and dynamic maneuvers.

The paper is well written. However, several issues remain.

Since the authors did not report personal data, but summarizes literature, this paper should be considered a review.

Since the paper is focused on oral cancer, the introduction must contain more details about oral cancer and focus on it.

Describing imaging techniques, the authors should report national and international guidelines about oral cancer.

If the authors report their protocols, they must compare them to others or to guidelines. Furthermore, they should describe advantages and disadvantages of different protocols.

A table with pros and cons of the imaging techniques may be useful to summarize data for the readers.

A Conclusion section is mandatory.

Author Response

AQ1 Since the authors did not report personal data, but summarizes literature, this paper should be considered a review.
R: Above the title of the manuscript in first page, we have corrected the category: no longer "Article" but "Review".

AQ2 Since the paper is focused on oral cancer, the introduction must contain more details about oral cancer and focus on it.
R: In the introduction we have included epidemiological, pathological, therapeutic data on oral cavity cancers, especially squamous cell carcinomas that are the most frequent oral carcinomas (90% of oral cavity neoplasms) [LINES 51-60].

AQ3 Describing imaging techniques, the authors should report national and international guidelines about oral cancer.
R: We have reported the recent guidelines drawn up by the United Kingdom-India oral cancer imaging group [Subramaniam 2021] and the recommendations by Drage et al. [Drage 2018]. Our protocols and descriptions of the imaging techniques in the text are in line with these guidelines. Therefore, indications found in “introduction”, “imaging techniques”, “MSCT and MRI acquisition protocols” sections are taken from these guidelines as specified in the text.

AQ4 If the authors report their protocols, they must compare them to others or to guidelines. Furthermore, they should describe advantages and disadvantages of different protocols.
R: We have now specified in the text that our protocols on the study of the oral cavity follow international directives. In fact, our protocols are in line with the recent guidelines drawn up by the United Kingdom-India oral cancer imaging group [Subramaniam 2021] and with the recommendations by Drage et al. [Drage 2018].
Furthermore, some technical parameters such as "FOV, matrix, acceleration factor, etc" have not been yet described in the literature on head-neck MRI examinations and therefore they are provided by our institute. However, such parameters obviously follow the indications of the guidelines above described. In addition, they are worthy of spreading across the world in an attempt to standardize ‒ thus make more reproducible and comparable ‒ examinations for the study of the oral cavity.

AQ5 A table with pros and cons of the imaging techniques may be useful to summarize data for the readers.
R: Thank you for the suggestion. We have added a table on pros and cons at the end of the paragraph on imaging techniques.

AQ6 A Conclusion section is mandatory.
R: The reviewer is right. You can now find conclusions section.

Reviewer 3 Report

This article is a mini-review about current imaging techniques of oral cavity including Multiline Spiral Computed Tomography (MSCT), Magnetic Resonance Imaging ( MRI) , cone-beam computed tomography (CBCT) , ultrasonic, Fluorine 18‐fluorodeoxyglucose 56 positron emission tomography (F-FDG PET) , and Dual Energy Computed Tomography (DECT). Some advanced MRI analysis techniques, including diffusion-weighted imaging (DWI) , dynamic contrast-enhanced perfusion-weighted imaging (DCE-PWI) , Open mouth technique and Puffed cheek technique, are well demonstrated by detailed context and figures. It is a very helpful article to put valuable advance knowledge of dental radiology together with clinical implications for all the readers. However, as a review where advanced techniques are summarized together, the article needs significant amount of revision and polish work.  Please refer to the comments below for a general guideline of revisions.

In general

1. The title of the article is “oral cavity imaging techniques, tricks and stratagems”. However, the contents can not support this title very well. The majority of tricks and strategies described in this article is about MRI system. Information of other imaging techniques are very briefly mentioned, or even brushed over, such as CBCT. Therefore, recommend authors to revise the title of the paper to emphasize on the main of focus of the content, or expand the content very well to support the title.
2. In abstract, one purpose of this article is to “propose MSCT and MRI acquisition protocols for an accurate study of the oral cavity area.”. The acquisitions used in this study center are generously shared in table 1 and table 2. However, authors should answer a few questions by sharing these parameters.

• are these parameters widely used standard settings in most countries?
• did the study center do any specific improvements of these settings before?
• why are these parameters worthy of spreading across the world?

3. MRI is a first-line radiology prescription in the oral surgery and pathology department, however, CBCT is a first-line radiology approach in routine dental clinic settings when dental providers suspected some oral lesions (except for pure soft tissue lesion). More comparisons of CBCT with MRI and MSCT are highly recommend being added into this article as a brief guideline to clinical providers, such as imaging details, radiation dose, metal-induced artifacts, etc.
4. A discussion and conclusion part should be added to the end of the article as an overall summarization.
5. 2.2 is well done. The information is clearly delivered by the context and figures. Highly recommend authors to revise other sections according to 4.2.2

In details

1. Figure 1 and figure 2:

• Machine settings for figure 1 and figure 2 should be listed.
• Please specify the machine technique in figure 1 legend and figure legend.

2. Please add a comparison of radiation doses of all radiographic methods discussed in this article as a fast clinical reference.
3. 2.1 please add DWI definitions
4. Line 244. Please attach a figure to demonstrate the content
5. Line 245: Please add demonstration of ADC maps
6. Please add figures to demonstrate DWI and the difference of DWI VS DECT
7. Line 523. Please specify the magnetic distortions and signal loss in figure 11 that was caused by dental materials.

 

 

Author Response

AQ7 The title of the article is “oral cavity imaging techniques, tricks and stratagems”. However, the contents can not support this title very well. The majority of tricks and strategies described in this article is about MRI system. Information of other imaging techniques are very briefly mentioned, or even brushed over, such as CBCT. Therefore, recommend authors to revise the title of the paper to emphasize on the main of focus of the content, or expand the content very well to support the title.
R: We have decided to revise the title of the paper to emphasize on the main focus of the content. The new title is as follows: Techniques, Tricks, and Stratagems of Oral Cavity Computed Tomography and Magnetic Resonance Imaging

AQ8 In abstract, one purpose of this article is to “propose MSCT and MRI acquisition protocols for an accurate study of the oral cavity area.”. The acquisitions used in this study center are generously shared in tables 1 and table 2. However, authors should answer a few questions by sharing these parameters.
Are these parameters widely used standard settings in most countries?
Did the study center do any specific improvements of these settings before?
Why are these parameters worthy of spreading across the world?
R:  We have now specified in the text that our protocols on the study of the oral cavity follow international directives. In fact, our protocols are in line with the recent guidelines drawn up by the United Kingdom-India oral cancer imaging group [Subramaniam 2021] and with the recommendations by Drage et al. [Drage 2018].
Furthermore, some technical parameters such as "FOV, matrix, acceleration factor, etc" have not been yet described in the literature on head-neck MRI examinations and therefore they are provided by our institute. However, such parameters obviously follow the indications of the guidelines above described. In addition, they are worthy of spreading across the world in an attempt to standardize ‒ thus make more reproducible and comparable ‒ examinations for the study of the oral cavity.

AQ9 MRI is a first-line radiology prescription in the oral surgery and pathology department, however, CBCT is a first-line radiology approach in routine dental clinic settings when dental providers suspected some oral lesions (except for pure soft tissue lesion). More comparisons of CBCT with MRI and MSCT are highly recommend being added into this article as a brief guideline to clinical providers, such as imaging details, radiation dose, metal-induced artifacts, etc.
R: CBCT is normally used for the assessment of dental and bone diseases including traumatic events, but not in case of oral cavity cancer. Therefore, in the text we have mentioned the following sentence “For this reason, a detailed analysis of CBCT was not investigated being beyond the purposes of our study” [LINES 154-155].
However, we have added some information about CBCT including CBCT artifacts vs MSCT artifacts (par. 6.1, LINES 584-587) and effective dose of CBCT examinations (see the paragraph on Imaging techniques, LINES 189-191).

AQ10 A discussion and conclusion part should be added to the end of the article as an overall summarization.
R: Each paragraph/section contains a discussion within it. For this reason, we did not dedicate a distinct section for discussion only.
We are really grateful with the reviewer to suggest us the conclusions, a fundamental section that we have now added.

AQ11 2.2 is well done. The information is clearly delivered by the context and figures. Highly recommend authors to revise other sections according to 4.2.2
R: We have revised some sections of our manuscript according 4.2.2 section. In addition, we have added some figures as follows:
- one on differences between artifacts in MSCT and CBCT;
- one on puffed cheek MRI technique;
- one on DWI of a palate tumor;
- one on DWI of a periapical cyst.
This way the discussion should be better delivered by figures.

AQ12 Machine settings for figure 1 and figure 2 should be listed. Please specify the machine technique in figure 1 legend and figure legend.
R: MSCT and MRI protocols used in the acquisition of each examination ‒ accompanied by the corresponding image (see Figures) ‒ are discussed in chapter 4 and schematized in Table 2 and 3. We have also added these information in the text [LINES 102-103].

AQ13 Please add a comparison of radiation doses of all radiographic methods discussed in this article as a fast clinical reference.
R: At the end of the paragraph on Imaging Techniques we have added information on the effective dose of each investigation involving the use of radiations [LINES 176-191].

AQ14 2.1 please add DWI definitions.
R: We have added DWI definition at the beginning of section 4.2.1 [288-291] as follows: “DWI measures the random Brownian motion of water molecules within a voxel of tissue, thus distinguishing highly cellular tissues with low diffusion coefficients (i.e. neo-plasms, with “restricted” diffusion) from scarcely cellular tissues with high diffusion coefficients (i.e. cystic or inflammatory diseases with free water diffusion)”.

AQ15 Line 244. Please attach a figure to demonstrate the content. Line 245: Please add demonstration of ADC maps. Please add figures to demonstrate DWI and the difference of DWI VS DECT
R: We have added a figure (Figure 4) to show the signal features (especially DWI-ADC map) of an oral cavity abscess. This figure shows the typical signal of the purulent content of an abscess. We have also added figures to demonstrate DWI/ADC maps and differences in DWI/ADC maps between different diseases including fig. 4 (odontogenic abscess), fig. 5 (SCC of the hard palate), fig. 6 (SCC of the floor of the mouth), and fig. 7 (periapical cyst).
Finally, we have included the discussion on DECT to make exhaustive our study on the oral cavity imaging techniques. We need to specify that DWI is a sequence belonged to MRI, whereas DECT is an innovative kind of computed tomography, therefore a comparison between them cannot be performed by figures. We reported in the text and Table 1 the advantages and disadvantages of each imaging technique.

AQ16 Line 523. Please specify the magnetic distortions and signal loss in figure 11 that was caused by dental materials.
R: The magnetic susceptibility artifact is described in figure 11 (now figure 16). To make the explanation of the artifact clearer, we have decided to modify the caption of figure 15 (now figure 21, pile-up artifact) showing also the central artifact with signal loss and distortion of the magnetic field. Please, see new figure 21.

Reviewer 4 Report

This manuscript summarizes the currently available imaging techniques for oral diseases, particularly  DWI, DCE-PWI, and dynamic manoeuvres. Authos also propose MSCT and MRI  acquisition protocols for a study of the oral cavity area.

The article contains some grammar errors. So it is recommended a complete english revision. Just a couple of examples of such errors:

[93] Bone and soft tissue algorithms have to always obtained... 

[266] reduce -> reduces

About the writing style; almost at the end of the manuscript, there can be found two bullets to separate paragraphs. Authors should standarize bullets in all the paper all no bullets at all.

Finally a Conclusion section is missing and needed to  summirize the main original contributions.

An interesting an useful work specially for the dentistry area.

Author Response

AQ17 The article contains some grammar errors. So it is recommended a complete english revision. Just a couple of examples of such errors:
[93] Bone and soft tissue algorithms have to always obtained
[266] reduce -> reduces
R: We have extensively revised English language as suggested by the reviewer.

AQ18 About the writing style; almost at the end of the manuscript, there can be found two bullets to separate paragraphs. Authors should standarize bullets in all the paper all no bullets at all.
R: We have standardized bullets in all the paper.

AQ19 Finally a Conclusion section is missing and needed to summirize the main original contributions.
R: The reviewer is right. You can now find conclusions section.

Round 2

Reviewer 2 Report

Thanks for improving the manuscript.

Reviewer 3 Report

The revisions were well executed. All issues in the review comments were addressed. Moreover, the authors added additional figures and tables to illustrate the contents which are very helpful.